Swansea: Manchester United lost for only the second time since November as Swansea came from behind to win 2-1 in the Premier League on Saturday.
Jonjo Shelvey grabbed the winner for Swansea in the 73rd minute, scoring a deflected shot from 25 meters to complete a league double for the Welsh side over United.
Shelvey set up South Korea midfielder Ki Sung-yueng for the equaliser in the 30th, canceling out Ander Herrera's opener for United two minutes earlier.
Since losing at Manchester City on Nov. 2, United's only defeat in 20 matches had come at home to Southampton.
The result saw United provisionally drop from third to fourth in the standings - and could be out of the Champions League qualification places completely if Southampton avoid defeat at home to Liverpool on Sunday.
United manager Louis van Gaal recalled Robin van Persie in place of the misfiring Radamel Falcao and played him alongside Wayne Rooney up front, although it was Swansea that looked more dangerous early on.
Marcos Rojo's poor pass set up Swansea playmaker Gylfi Sigurdsson, whose shot was blocked, before Bafetimbi Gomis lost his marker at the resulting corner to power a header that Herrera hacked off the line.
United seized the lead when some fine approach play ended with Rooney finding Angel di Maria and the Argentina international set up Herrera's fifth goal for United, and his second in as many games.
Swansea's reply was quick as Shelvey crossed from the left and Ki, just as he had done at Old Trafford in August, scored by getting across Luke Shaw and sweeping the ball home.
Van Gaal's response to try to achieve dominance was to put on fresh legs at full back, with Ashley Young replacing Shaw after Antonio Valencia had been introduced at half-time for Paddy McNair.
United enjoyed the majority of possession and started creating more chances, through Van Persie and Rojo.
Swansea were clinging on but relieved the pressure and struck against the run of play after 73 minutes when Shelvey's powerful strike beat De Gea with the aid of a deflection off Gomis.